[President] Trump tweeted over the weekend that he knew then-national security adviser Michael Flynn lied to the FBI about his contacts with the Russian ambassador before firing him in February — and before FBI Director James B. Comey said Trump asked him to be lenient while investigating Flynn. Experts said the president’s admission increased his legal exposure to obstruction-of-justice charges, one of the core crimes under investigation by special counsel Robert S. Mueller III.

But Trump’s personal lawyer John Dowd sought to excuse the president’s tweet in part by telling Axios and NBC News on Monday that the “president cannot obstruct justice because he is the chief law enforcement officer under [the Constitution’s Article II] and has every right to express his view of any case.”

This apparently caught White House staff off-guard. (“Some senior officials were baffled that Dowd publicly offered this interpretation of the law, which has been advanced since the summer by constitutional scholar Alan Dershowitz in defense of Trump but flatly dismissed by many other legal scholars.”)

It’s not just scholars. President Richard Nixon was an unindicted co-conspirator in the Watergate case. The prosecution did not choose to charge him at that time (more about that in a minute), but a co-conspirator is plainly someone who has committed a crime. Moreover, as Noah Bookbinder, Norman Eisen and Barry Berke point out in their brief on the subject, law enforcement officials of various types have the power to perform certain actions but not with corrupt intent (e.g. a police officer who arrests citizens who don’t pay bribes). The president is no different. (Let’s recall that Attorney General John Mitchell was convicted of, among other crimes, obstruction of justice.) And let’s recall that President Gerald Ford pardoned Nixon so that he wouldn’t be prosecuted for obstruction of justice while in office.

All we need to observe is that in the context of a properly predicated national security investigation in which evidence of major criminality had arisen and in which more than one witness had already lied to the FBI, the FBI director alleged that the President had asked him for a pledge of loyalty and had cleared the room and asked the FBI director to go easy on one of the people who had lied to the Bureau and that he had otherwise put pressure on law enforcement leadership on the conduct of the case. We observe further that he stayed in touch with the witness in question and even told him to “stay strong.” We observe that he fired the FBI director, reportedly boasted to the Russian government that he had relieved pressure on himself by doing so, and he then continued to the threaten and bully the law enforcement leadership over the specific matter at issue. So here’s my fourth question for Dershowitz: Given this pattern of behavior and the fact that certain efforts to obstruct an investigation—for example, witness tampering—are decidedly not within the purview of the presidential role in supervising the Executive Branch, should the Mueller investigation have entirely declined even to look at the President’s pattern of behavior with respect to the Russia investigation?

My broad point here is that this is conduct that in any other context the FBI would be all over.

In sum, we simply have never believed or acted as though the president cannot commit crimes in office. There is a separate question as to whether the president can be prosecuted while in office. (Maybe Dowd, who has already proved to be sloppy and reckless, got confused between the two.) Special Watergate prosecutor Leon Jaworski didn’t think you could indict a sitting president, so he made an impeachment referral. That view remains the official Justice Department position, although legal scholars have debated its merits. John P. Carlin wrote for The Post in June:

First in 1973 with President Richard M. Nixon, and then again in 2000 with President Bill Clinton, the [Justice Department’s Office of Legal Counsel] determined that the indictment or prosecution of a sitting president “would be unconstitutional because it would impermissibly interfere with the President’s ability to carry out his constitutionally assigned functions.” Despite its Nixon-era origins, the theory is not that the president is above the law, but rather that any criminal case must wait until after he or she leaves office.

The issue is one of separation of powers. Although the Constitution sets out a mechanism by which Congress may remove the president — the impeachment process — any attempt to prosecute the commander in chief before he or she leaves office would, in the OLC’s view, constitute an unworkable intrusion into the president’s core responsibilities. Both in 1973 and 2000, the OLC analysis noted that the presidency is unique because the executive branch is ultimately led by a singular figure on call and on the job 24 hours a day, unlike Congress or the judiciary. If one or more members of the legislative or judicial branches are temporarily distracted, others on the job can step in to keep business going.

A president can be impeached, of course, for criminal conduct — or for conduct that doesn’t reach the level of a criminal violation. The president can then be prosecuted when he leaves office (hence the need for Ford’s pardon). No one can doubt that Trump could be impeached for obstruction of justice, and that, if Mueller finds the goods, is where this could well be heading. Telling his client and the country that a president can’t commit obstruction gives false comfort to the president and his supporters. Now, perhaps that is the intent — to convince his base that a president cannot, in essence, commit a crime so that when he is impeached and/or later prosecuted, his loyalists will rise up in fury.

Then again, maybe Dowd simply has no idea what he is doing. Trump really should get a competent counsel. He needs one.